Description: (Applicant's Description) The Cell Resources Core (CRC) provides Comprehensive Cancer Center members, and national and international cancer researchers, access to cell resources that are both key to cancer research and in many cases unique, and to services that enhance accomplishment of their cancer research. The CRC was established to provide investigators the estrogen-responsive MCF-7 human breast cancer cell line and MCF10-A/F non- tumorigenic human breast epithelial cell lines. The scope of resources continues to expand through the expertise of the current staff, Robert J. Pauley, Director, and Steven J. Santner, which is substantiated by their publications. New unique resources include highly tumorigenic derivatives of MCF-10A, mortal fibroblast and epithelial cells and cell lines from human tissues including reduction mammoplasty and benign breast tissues, and human pancreatic tumors. Services available include scientific consultation and assistance with acquisition of new cell resources, toxicity testing for microchip gene expression analyses, clonogenic assays testing therapeutic response, and establishment of cultures from breast tissues. Investigators from all programs have received resources and/or services. The 49 cited publications provide evidence of significant benefit and stimulation of scientific interactions. It is the quality of the resources, the ability to develop new and unique resources, and the availability of specialized services that demonstrate the benefit of the Cell Resources Core to Comprehensive Cancer Center Members.